创建表时出现hibernate异常

时间：2017-06-24 17:58:07

标签： java mysql hibernate

按照yt频道上的教程，我尝试使用Hibernate创建一个简单的应用程序。当我执行代码时，我得到了一堆异常，我无法确定原因。但是，创建表和插入数据的结果是可见的，并且工作正常 - 这让我感到困惑。下面我提供必要类的代码，persistence.xml和堆栈跟踪。我该如何解决这个问题？

STACK TRACE:
    cze 24, 2017 7:39:31 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlString(SchemaDropperImpl.java:375)
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlStrings(SchemaDropperImpl.java:359)
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applyConstraintDropping(SchemaDropperImpl.java:331)
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.dropFromMetadata(SchemaDropperImpl.java:230)
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.performDrop(SchemaDropperImpl.java:154)
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:126)
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:112)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:144)
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:309)
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:452)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:889)
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:58)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:39)
    at org.hibernate.test.Main.main(Main.java:12)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'hibernate_tests.employee' doesn't exist
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.Util.getInstance(Util.java:408)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:943)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2486)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2444)
    at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:845)
    at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:745)
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54)
    ... 16 more

cze 24, 2017 7:39:31 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@363042d7] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
cze 24, 2017 7:39:31 PM org.hibernate.tool.schema.internal.SchemaCreatorImpl applyImportSources
INFO: HHH000476: Executing import script 'org.hibernate.tool.schema.internal.exec.ScriptSourceInputNonExistentImpl@59d2400d'
cze 24, 2017 7:39:31 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl stop
INFO: HHH10001008: Cleaning up connection pool [jdbc:mysql://localhost:3306/hibernate_tests]

persistence.xml 

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="myDatabase" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
    <properties>
        <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
        <property name="javax.persistence.jdbc.user" value="miki" />
        <property name="javax.persistence.jdbc.password" value="***" />
        <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/hibernate_tests" />
        <property name="hibernate.dialect.storage_engine" value="innodb" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL57Dialect" />
        <property name="hibernate.hbm2ddl.auto" value="create" />
    </properties>
</persistence-unit>

Main.java 

public class Main {

public static void main(String[] args) {
    EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("myDatabase");
    EntityManager entityManager = entityManagerFactory.createEntityManager();

    Employee employee = new Employee();
    Address address = new Address();
    employee.setAddress(address);
    employee.setFirstName("aaa");
    employee.setLastName("bbb");
    employee.setSalary(10000);

    address.setLocalization("ccc");
    address.setStreet("ddd");
    address.setPostalCode("12-456");

  /*  entityManager.getTransaction().begin();
    entityManager.persist(address);
    entityManager.persist(employee);
    entityManager.getTransaction().commit();*/

    entityManager.close();
    entityManagerFactory.close();
}

}

Employee.java 

@Entity
public class Employee {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
@Column(name = "Imie")
private String firstName;
@Column(name = "Nazwisko")
private String lastName;
@Transient
private double salary;
@OneToOne
@JoinColumn
private Address address;

/*sett.&gett*/
}

Address.java 

@Entity
public class Address {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;

@Column(name = "Miejscowosc")
private String localization;
@Column(name = "Ulica")
private String street;
@Column(name = "Kod_Pocztowy")
private String postalCode;
/*sett.&gett.*/

2 个答案:

答案 0 :(得分：0)

首先确保您的数据库hibernate_tests包含表employee，其次要确保将表的名称放在实体中，如：

@Entity
@Table(name = "employee", catalog = "hibernate_tests", schema = "schema_name")
public class Employee {...}

如果您有默认架构，那么您不需要使用它：

@Entity
@Table(name = "employee")
public class Employee {...}

如果仍然无效，您可以使用数据库名称进行检查：

@Entity
@Table(name = "employee", catalog = "hibernate_tests")
public class Employee {...}

答案 1 :(得分：0)

我设法找到导致问题的原因。每次执行java代码之前，我都会手动删除表。当程序执行时，休眠首先尝试删除表，假设它们存在于数据库中。由于我之前删除了它们，因此表格不存在。 当我不手动删除表时，没有例外。

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